Button and more

* Add button that toggles active/inactive mode
* Rename hers/his as yang/yin (stop dictating genders)
* Different colors and scan animations for yin&yang

README.md

 ### Blinkinlove Materix
 
-_Blinkinlove_ (_אהיבהוב_) is a line of technoromantic jewlery by [zzzen](https://zzzen.com): these accessories come in pairs, and each can blink in a heartbeat rhythm in order to indicate that it can sense that its mate is nearby. The closer the mate is, the faster the blinking. It looks for its mate by performing a wifi or bluetooth scan ()depending on the model).
+_Blinkinlove_ (_אהיבהוב_) is a line of technoromantic jewlery by [zzzen](https://zzzen.com): these accessories come in pairs, and each can blink in a heartbeat rhythm in order to indicate that it can sense that its mate is nearby. The closer the mate is, the faster the blinking. It looks for its mate by performing a wifi or bluetooth scan (depending on the model).
 
 The _Materix_ model is built on an [Adafruit Feather HUZZAH](https://www.adafruit.com/product/2821) board (with wifi capabilities) with a 4x8 [Neopixel Matrix Featherwing](https://www.adafruit.com/product/2945). For blinking, it uses a heart-shaped Neopixel animation.
 
 ![Blinkinlove Materix when close to mate](blinkinlove-materix.gif)
 
-Whenever it perfoms a scan, there's a blue indication on the right hand side. When the mate is nearby, this indication is limited to a single pixel, but when the mate can't be found, this becomes a more elaborate "where art thou" animation.
+Whenever it perfoms a scan, there's an indication on the right hand side. When the mate is nearby, this indication is limited to a single pixel, but when the mate can't be found, this becomes a more elaborate "where art thou" animation.
+
+The colors and animations are personalized for each mate, to express that they're connected, but not identical.
+
+![Blinkinlove Materix desperately seeking mate](blinkinlove-materix-alone.gif)
+
+### Activation button
+![Activation button](activation-button.jpg)
+
+There's a button that activates/deactivates scan and display functionality (the device always maintains a WiFi access point so that it can be detected by its mate). This saves battery, and also gives the wearer the ability not to be flashing and blinking (handy in many situations).
+
+After a reset (e.g. when you start charging an empty battery), the materix enters the inactive state (after a vanity scroll of the text "zzzen"), and you'll need to press the button in order to activate it.
+
+
 
-![Blinkinlove Materix desperately seeking mate](blinkinlove-materix-alone.gif)

blinkinlove-materix.ino

 /*********
- * Blinkinlove / Materix
- * Techno-romantic jewelery based on
- * Adafruit Feather HUZZAH boards and
- * 4*8 NeoPixel Matrix FeatherWings
+   Blinkinlove / Materix
+   Techno-romantic jewelery based on
+   Adafruit Feather HUZZAH boards and
+   4*8 NeoPixel Matrix FeatherWings
  *********/
 
+#define DEBUG true
+
+#define BUTTON_PIN 2
+#define PSEUDO_GND 14 // physically close to button. Set to LOW at setup
+#define DEBOUNCE_MILLIS 250
+unsigned long last_press = 0;
+bool is_active = false;
+
+
 #include "config.h"
 
 #include <Adafruit_NeoPixel.h>
 int current_frame = 0;
 unsigned long last_flip = 0;
 
-#define NUM_SCAN_PIXELS 4
-int scan_pixels[NUM_SCAN_PIXELS] = { 31, 23, 15, 7 };
 #define SCAN_FRAME_DURATION 200
+#define SCAN_COMMON_COLOR_YANG strip.Color(16, 32, 64)
+#define SCAN_ANIM_COLOR_YANG strip.Color(16, 32, 128)
+#define SCAN_COMMON_COLOR_YIN strip.Color(64, 32, 16)
+#define SCAN_ANIM_COLOR_YIN strip.Color(128, 32, 16)
+
+#define NUM_SCAN_ANIM_FRAMES 4
+
+int scan_yang_common[] = { 31, -1};
+int scan_yang_frame_a[] = { 23, -1};
+int scan_yang_frame_b[] = { 15, -1};
+int scan_yang_frame_c[] = { 7, -1};
+int scan_yang_frame_d[] = { -1};
+
+int *scan_anim_frames_yang[NUM_SCAN_ANIM_FRAMES] = {
+  scan_yang_frame_a,
+  scan_yang_frame_b,
+  scan_yang_frame_c,
+  scan_yang_frame_d
+};
+
+int scan_yin_common[] = { 31, -1};
+int scan_yin_frame_a[] = { 30, -1};
+int scan_yin_frame_b[] = { 22, -1};
+int scan_yin_frame_c[] = { 23, -1};
+
+int *scan_anim_frames_yin[NUM_SCAN_ANIM_FRAMES] = {
+  scan_yin_frame_a,
+  scan_yin_frame_b,
+  scan_yin_frame_c,
+  scan_yin_frame_b
+};
+
 
 
 // Zzzen vanity logo (scrolls after reset)
 void scrollZzzen(int offs) {
   for (int y = 0; y < 4; y++) {
     for (int x = 0; x < 8; x++) {
-      int xoffs = x+offs, level = 0;
-      if (xoffs>=0 && xoffs<24) {
-        level = zzzen[24*y+xoffs];
+      int xoffs = x + offs, level = 0;
+      if (xoffs >= 0 && xoffs < 24) {
+        level = zzzen[24 * y + xoffs];
       }
       strip.setPixelColor(8 * y + x, strip.Color(0, 0, level));
     }
 #define RSSI_FAR -100
 int rssi = 0;
 bool scanning = false;
+bool is_yang;
 
 // set rssi to mate's rssi (0 if not found)
 void checkScanResult(int numResults) {
     current_frame = 0;
   }
   if (scanning) {
-    if (rssi) {
-      strip.setPixelColor(scan_pixels[0], strip.Color(0, 0, 16));
-    } else {
-      int bright = (nowmillis / SCAN_FRAME_DURATION) % NUM_SCAN_PIXELS;
-      for (int i = 0; i < NUM_SCAN_PIXELS; i++) {
-        int blueness = i == bright ? 64 : i < bright ? 16 : 0;
-        strip.setPixelColor(scan_pixels[i], strip.Color(0, 0, blueness));
+    // Show scanning indication
+    int *frame = is_yang ? scan_yang_common : scan_yin_common;
+    for (int i = 0; frame[i] >= 0; i++) {
+      strip.setPixelColor(frame[i], is_yang ? SCAN_COMMON_COLOR_YANG : SCAN_COMMON_COLOR_YIN);
+    }
+    if (!rssi) {
+      int frame_index = (nowmillis / SCAN_FRAME_DURATION) % NUM_SCAN_ANIM_FRAMES;
+      frame = is_yang ? scan_anim_frames_yang[frame_index] : scan_anim_frames_yin[frame_index];
+      for (int i = 0; frame[i] >= 0; i++) {
+        strip.setPixelColor(frame[i], is_yang ? SCAN_ANIM_COLOR_YANG : SCAN_ANIM_COLOR_YIN);
       }
     }
-    strip.show();
   }
+  strip.show();
 }
 
-
 void setup()
 {
   Serial.begin(115200);
   delay(1000);
 
+  pinMode(BUTTON_PIN, INPUT_PULLUP);
+  pinMode(PSEUDO_GND, OUTPUT);
+  digitalWrite(PSEUDO_GND, LOW);
+
   strip.begin();           // INITIALIZE NeoPixel strip object (REQUIRED)
-  strip.setBrightness(32); // (max = 255)
+  strip.setBrightness(16); // (max = 255)
   strip.show();            // Turn OFF all pixels ASAP
 
   for (int offs = -23 ; offs < 25; offs++) {
     scrollZzzen(offs);
     delay(100);
   }
-  
+
   my_mac = WiFi.softAPmacAddress();
   if (DEBUG) {
     Serial.print("My MAC: ");
     Serial.println(my_mac);
   }
-  if (my_mac.equals(HERS)) {
-    mate_mac = String(HIS);
+  if (my_mac.equals(YIN)) {
+    is_yang = false;
+    mate_mac = String(YANG);
   } else {
-    mate_mac = String(HERS);
+    is_yang = true;
+    mate_mac = String(YIN);
   }
   WiFi.softAP(String("blinkinlove:") + my_mac.substring(12), "whereartthou");
-
 }
 
 void loop()
 {
   unsigned long nowmillis = millis();
-  if (nowmillis > next_scan) {
+  if ((nowmillis < last_press || nowmillis > last_press + DEBOUNCE_MILLIS) && digitalRead(BUTTON_PIN) == LOW) {
+    last_press = nowmillis;
+    is_active = !is_active;
     if (DEBUG) {
-      Serial.print("Scanning for ");
-      Serial.println(mate_mac);
+      Serial.print("is_active set to ");
+      Serial.println(is_active);
+    }
+    if (!is_active) {
+      for (int i = 0; i<NEOPIXEL_COUNT; i++) {
+        strip.setPixelColor(i,strip.Color(0,0,0));
+      }
+      strip.show();
+    }
+
+  }
+  if (is_active) {
+    if (nowmillis > next_scan) {
+      if (DEBUG) {
+        Serial.print("Scanning for ");
+        Serial.println(mate_mac);
+      }
+      scanning = true;
+      WiFi.scanNetworksAsync(checkScanResult);
+      next_scan = nowmillis + SCAN_INTERVAL;
     }
-    scanning = true;
-    WiFi.scanNetworksAsync(checkScanResult);
-    next_scan = nowmillis + SCAN_INTERVAL;
+    animate(rssi, scanning, nowmillis);
   }
-  animate(rssi, scanning, nowmillis);
   delay(20);
 }

config-example.h

 // [If you haven't done so already] copy config-example.h to config.h
 
 // When DEBUG is true, board's MAC address is printed to serial
-// Once you copy MAC addresses of both mates, use them as HIS/HERS below.
+// Once you copy MAC addresses of both mates, use them as YIN/YANG below.
 // You can then upload the same code to both mates (each would know to
 // scan for the other one, and not for itself).
 
-#define HIS "11:22:33:44:55:66"
-#define HERS "ff:ee:dd:cc:bb:aa"
+#define YIN "11:22:33:44:55:66"
+#define YANG "ff:ee:dd:cc:bb:aa"